142 research outputs found
A new impedance matching method for an ultra-wide band and dual circularly polarised feed
In traditional antenna design, metal components are not placed in the central part of the antenna as they change the characteristics of near field radiation. However, we show that placing a metal ring in the centre of the strip lines, which connect the ends of folded high-frequency dipoles, does not damage the performance of the feed. Instead it significantly improves the voltage standing wave ratio of the feed whilst other performance indicators are not compromised. Thus, our findings show an excellent way of improving the wide band feed. Based on this foundation, a new circularly polarised feed for operation between 0.4 to 2 GHz is introduced for the Chinese Spectral Radioheliograph in this paper. The issue of a feed impedance matching network is investigated. By optimising the impedance matching, the performance of the feed is enhanced with respect to the previous realisations of the Eleven feed. The simulation and experimental results show that the gain of the feed is about 10 dBi, and the VSWR is less than 2:1. In addition, the feed has a low axial ratio, fixed phase centre location, and constant beam width in the range of 0.4 to 2 GHz
Device modeling of superconductor transition edge sensors based on the two-fluid theory
In order to support the design and study of sophisticated large scale
transition edge sensor (TES) circuits, we use basic SPICE elements to develop
device models for TESs based on the superfluid-normal fluid theory. In contrast
to previous studies, our device model is not limited to small signal
simulation, and it relies only on device parameters that have clear physical
meaning and can be easily measured. We integrate the device models in design
kits based on powerful EDA tools such as CADENCE and OrCAD, and use them for
versatile simulations of TES circuits. Comparing our simulation results with
published experimental data, we find good agreement which suggests that device
models based on the two-fluid theory can be used to predict the behavior of TES
circuits reliably and hence they are valuable for assisting the design of
sophisticated TES circuits.Comment: 10pages,11figures. Accepted to IEEE Trans. Appl. Supercon
Variations in incidence of venous thromboembolism in low-, middle-, and high-income countries
AimsTo examine the rates of venous thromboembolism (VTE) in high-income, upper middle-income, and lower middle/low-income countries (World Bank Classification).Methods and ResultsWe examined the rates of VTE in high-income, upper middle-income, and lower middle/low-income countries (World Bank Classification) in a cohort derived from four prospective international studies (PURE, HOPE-3, ORIGIN, and COMPASS). The primary outcome was a composite of pulmonary embolism, deep vein thrombosis, and thrombophlebitis. We calculated age- and sex-standardized incidence rates (per 1000 person-years) and used a Cox frailty model adjusted for covariates to examine associations between the incidence of VTE and country income level. A total of 215Â 307 individuals (1.5 million person-years of follow-up) from high-income (nâ=â60Â 403), upper middle-income (nâ=â42Â 066), and lower middle/low-income (nâ=â112Â 838) countries were included. The age- and sex-standardized incidence rates of VTE per 1000 person-years in high-, upper middle-, and lower middle/low-income countries were 0.87, 0.25, and 0.06, respectively. After adjusting for age, body mass index (BMI), smoking, antiplatelet therapy, anticoagulant therapy, education level, ethnicity, and incident cancer diagnosis or hospitalization, individuals from high-income and upper middle-income countries had a significantly higher risk of VTE than those from lower middle/low-income countries [hazard ratio (HR) 3.57, 95% confidence interval (CI) 2.40-5.30 and HR 2.27, 95% CI 1.59-3.23, respectively]. The effect of country income level on VTE risk was markedly stronger in people with a lower BMI, hypertension, diabetes, non-White ethnicity, and higher education.ConclusionThe rates of VTE are substantially higher in high-income than in low-income countries. The factors underlying the increased VTE risk in higher-income countries remain unknown.</div
AllâInâOne OsciDrop Digital PCR System for Automated and Highly Multiplexed Molecular Diagnostics
Digital PCR (dPCR) holds immense potential for precisely detecting nucleic acid markers essential for personalized medicine. However, its broader application is hindered by high consumable costs, complex procedures, and restricted multiplexing capabilities. To address these challenges, an allâinâone dPCR system is introduced that eliminates the need for microfabricated chips, offering fully automated operations and enhanced multiplexing capabilities. Using this innovative oscillationâinduced droplet generation technique, OsciDrop, this system supports a comprehensive dPCR workflow, including precise liquid handling, pipetteâbased droplet printing, in situ thermocycling, multicolor fluorescence imaging, and machine learningâdriven analysis. The system's reliability is demonstrated by quantifying reference materials and evaluating HER2 copy number variation in breast cancer. Its multiplexing capability is showcased with a quadruplex dPCR assay that detects key EGFR mutations, including 19Del, L858R, and T790M in lung cancer. Moreover, the digital stepwise melting analysis (dSMA) technique is introduced, enabling highâmultiplex profiling of seven major EGFR variants spanning 35 subtypes. This innovative dPCR system presents a costâeffective and versatile alternative, overcoming existing limitations and paving the way for transformative advances in precision diagnostics
Climatic and anthropogenic regulation of carbon transport and transformation in a karst river-reservoir system
The effect of dams on dissolved inorganic carbon (DIC) transport and riverine ecosystems is unclear in karst cascade reservoirs. Here, we analyzed water samples from a karst river system with seven cascade reservoirs along the Wujiang River, southwestern China, during one hydrological year. From upstream to downstream, the average concentration of DIC increased from 2.2 to 2.6 mmol/L and its carbon isotope composition (δ13CDIC) decreased from â8.0 to â10â°. Meanwhile, the air temperature (Ta) increased from 20.3 °C to 26.7 °C and 10 °C to 13.7 °C in the warm and cold seasons, respectively. The results suggest that a cascade of dams has a stronger effect on DIC dynamics and retention than a single dam. The good correlation between Ta/HRT (hydraulic retention time) and Î[DIC] as well as Î[δ13CDIC] mean that Ta and HRT affected the magnitude of the damming effect by altering changes in concentration of DIC and δ13CDIC in the reservoir compared to the inflowing water. In particular, daily regulated reservoirs with short retention times acted more like river corridors and had a smaller effect on carbon dynamics, so modulating retention time might be used reduce the effect of dams on the riverine ecosystem
Association Between the Lipid Profile and Renal Dysfunction in the Heart Failure Patients
Background/Aims: In heart failure patients with high prevalence of chronic renal disease (CKD), hospitalization and mortality, whether the lipid profile was associated with renal dysfunction remained unknown. The present study intended to clarify the association between the lipid profile and renal dysfunction in the heart failure patients. Methods: 336 hospitalized heart failure patients with left ventricle ejection fraction (LVEF) â¤45% and New York Heart Association (NYHA) class II-IV were enrolled. The estimated glomerular filtration rate (eGFR) < 90 mL/min¡1.73 m2 was defined as renal dysfunction. The demographic, clinical data, blood samples and echocardiography were documented. The Pearson simple linear correlation was performed to evaluate the confounding factors correlated with eGFR. The significantly correlated factors were enrolled in Logistic regression as confounding factors to determine the association between the lipid profile and renal dysfunction in the heart failure patients. Results: 182 patients (54.2%) had renal dysfunction and 154 patients (45.8%) did not have renal dysfunction. The waist circumference, platelet counts, platelet distribution width (PDW), high density lipoprotein-cholesterol (HDL-C), apolipoprotein A1 (apoA1), albumin and left ventricular ejection fraction (LVEF) are positively correlated with eGFR (all P< 0.05). Meanwhile, the age, mean platelet volume (MPV), neutrophilic granulocyte percentage (NEUT%), urea nitrogen (BUN), creatinine and total bilirubin (TBIL) are negatively correlated with eGFR (all P< 0.05). The total cholesterol (TC), triglyceride, low density lipoprotein-cholesterol (LDL-C) and apolipoprotein B (apoB) show no correlation with eGFR. After the adjustment of sex, hypertension, diabetes mellitus, age, waist circumference, platelet counts, MPV, PDW, NEUT%, TBIL, albumin and LVEF, HDL-C is the only lipid factor still significantly associated with renal dysfunction in hospitalized heart failure patients (OR=0.119, P=0.003). Conclusion: Among the lipid profile of TC, triglyceride, LDL-C, HDL-C, apo A1 and apo B, the HDL-C is the only lipid factor significantly associated with renal dysfunction in hospitalized heart failure patients
Stabilization by Fusion to the C-terminus of Hyperthermophile Sulfolobus tokodaii RNase HI: A Possibility of Protein Stabilization Tag
RNase HI from the hyperthermophile Sulfolobus tokodaii (Sto-RNase HI) is stabilized by its C-terminal residues. In this work, the stabilization effect of the Sto-RNase HI C-terminal residues was investigated in detail by thermodynamic measurements of the stability of variants lacking the disulfide bond (C58/145A), or the six C-terminal residues (ÎC6) and by structural analysis of ÎC6. The results showed that the C-terminal does not affect overall structure and stabilization is caused by local interactions of the C-terminal, suggesting that the C-terminal residues could be used as a âstabilization tag.â The Sto-RNase HI C-terminal residues (-IGCIILT) were introduced as a tag on three proteins. Each chimeric protein was more stable than its wild-type protein. These results suggested the possibility of a simple stabilization technique using a stabilization tag such as Sto-RNase HI C-terminal residues
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